1. pk123

    pk123 Member

    Joined:
    Oct 21, 2019
    32
    29
    0
    Location:
    Washington
    Vehicle:
    2010 Prius
    Model:
    II
    The front driver side rotor gets hot (possible to touch quickly, but not touch and hold) when driving. Front passenger side gets warm. Rear rotors stay cool. But there is a noticeable temperature difference on the front driver side.

    Is this variation normal, or do I have a problem?

    When the front is jacked up and gear is in neutral, the driver side wheel spins without much resistance, including after pressure is applied (and released) on the brake.

    Fuel economy is subpar: 40-42mpg on highway in summer weather. Battery capacity per Dr. Prius is 56%.

    Check-engine light is on but only due to the annoying P0456 code.

    This is a 2010 Gen 3 with 226k miles. It has been religiously serviced; spark plugs changed at 150k, no noticeable oil consumption or coolant escape.

    Any feedback greatly appreciated!
     
  2. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    26,244
    17,186
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    In this post you will find how to do a sensitive test that I use for brake drag. The ideal result from that test is for all four rotors to be stone cold to the touch.

    Key to the test is coming to a stop with absolutely no use of the brakes (other than stabbing them right at 0 mph to keep the car stopped). Even a little braking to bring the car to a stop will make a difference you can feel, reducing the usefulness of the test.
     
    pk123 likes this.
  3. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    58,765
    40,462
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Periodic brake service done?

    Toyota USA's vague, but a close look at the schedule, you'll see the "visual" brake inspection that's noted every 5k (or 6 mo) is replaced by a more serious sounding (but vague) mention of checking rotors, etcetera, at 30k mile intervals (or tri-yearly).

    A 2010 with 226k miles and no oil consumption, you must be doing something right. EGR ever cleaned? See you were asking about the latter, back a few years.
     
    #3 Mendel Leisk, Jun 18, 2025 at 11:34 AM
    Last edited: Jun 18, 2025 at 11:43 AM
    pk123 likes this.
  4. pk123

    pk123 Member

    Joined:
    Oct 21, 2019
    32
    29
    0
    Location:
    Washington
    Vehicle:
    2010 Prius
    Model:
    II
    No, I cleaned the intake manifold and EGR pipe but chickened out when it came to removing the actual valve. You think that could be causing such a big drop in efficiency?
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    58,765
    40,462
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Efficency drop's more likely due to dragging brake.

    With 226k it's somewhat amazing the engine's still running. No coolant loss, cold-start shaking? C'mon, I don't want to be eating crow for lunch.